Example of active transport would be a. osmosis
b. diffusion
c. sodium-potassium pumps
d. facilitated diffusion

c. sodium-potassium pump

Explanation:

a. osmosis - this is a type at of passive transport. It is diffusion specific to water molecules.

b. diffusion - this is also a type of passive transport. Molecules move from a high concentration to a low concentration down a concentration gradient. This is passive transport and does not require energy.

c. A sodium-potassium pump is a type of active transport, it uses energy to move ions across the membrane. They cannot pass through the membrane because they are charged.

d, facilitated diffusion is a type of passive transport through which substances are transported through proteins in the plasma membrane.

the dark variety, as they are not visible on the dark tree barks

explanation: